Thermo--explobive cartridge



Hl RUDD 3 Sheets-Sheen 1.

@si w C. THERMO-*EXPLOSIVE CARTRIDGE.

iNo ModeM No.. i/Ql.

No Model.) 3 SlweLs-Slleet 2 G. H. RUDD. THBRMO-EXPLOSIVB CARTRIDGE.

Patent-ed Mag. 24, 1896.

90 D D R H C 'THERMO-EXPLOSIVE CARTRIDGE.

l. Patented Mar. 24, 1896.

Nitro' Sir-iras IFICB.

CHARLES ll. 'RI/TDD, OF CHICAGO, ILLINOIS, ASSIGNOR TO 'lif'l WES'RERN ELECTRIC COMPANY, OF SAME PLACE.

THERMOEXPLOSWE CARTRIDGE.

SPECIFICATION forming part of Lettera atsht No. 558,901, dated March 24, 1898.4

Application iiled December 26, 1893.

.'lo all whom it may concern..

lle it known that I, CHARLES Il. RUDD, a citizen of the Unit-ed States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Thermo Explosive Cartridges, (Case No. 32,) of which the following is a full, clear, concise,- a-nd exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention rela tes to an improved means for and method of preparing for and producing explosions. p

Through the method of my inventionl am enabled to make use of materials which are not classed as eiplosive, and which under ordinary conditions and at ordinary temperatures are perfectly safe to handle.' My iiivention is applicable likewise to the wellknown explosives, and its advantages when used either with explosive or non-explosive materials, so called,will be made apparent through the description which follows.

Broadly considered and, briefly stated, my

invention consists in augmenting thea'iolen ce of the chemical combination of explosive ma teria-ls by means of heat applied to and stored n p in the materials after they are inthe place where itis desirable that the explosion shall take place. connection with the application of heat vby means of the electric current, which is the manner of heating which I prefer to employ; but my invention is not limited to the particular method in which the electric current is employed for the heating.

To enable those skilled in the arts to which my invention relates to practice my invern tion, I will describe it as applied to producing 'explosions in blasting, it being readily understood that the same process may be used for-other purposes where the explosive force ot' chemical combinations taking place in confined spaces is employed, nud while I shall describe with particularity the specific details of the means I` preferably employ in Refcrringito the accompanying drawings,

I shall describe the method in Serial No. 494,725. (No specimens.)

Figure lis a partial sectional elevation of one form of the cartridge with part of the explosive material removed to clearly reveal the positionv of the poils. Fig. 2 is a plan view of the same. Fig. 3 is a sectional plan 55 view on line .r .1' of Fig. '1 with the coils shown in full plan. Fig. 4t is a detail sectional view of the igniter. Fig. 5 is a longitudinal -sectional View of a similar cartridge having a different arrangement of the heating-coils. 6o Fig. G is a plan ot' this form of cartridge; and Fig. 7is a section on the line y y, Fig. 5. Fig. 8 is an igniter with the igniting-wires ar` ranged in a manner similar to those in the cartridge of Fig. Fig. 9 shows in dia- 65 grammati'c form -`the circuits connecting the coils and the exploder Within the shell of the cartridge with the source of electricity.

In all the views like parts are designated by similar letters of reference.

AFor a casing or shell of a cartridge ai, I use in practice iron tubes, and for eheapness and convenience I have found old boiler-fiues readily available. For purposes of insulation, both with respect to heat and electricity, I line the shell of the cartridge with thick paper b. The cartridge-case itself `night be made of paper or wood, or of other suitable material. In using iron tube I have preferred to close the ends by driving in soft 8o wooden plugs c c, as seen in Fig. 1,by screwpressure. In an alternativeplanl have closed the ends by screw-caps d d, as shown in Fig. 5. I fillv the cartridge-shell with a charge containing in suitable proportions elements having the necessary chemical affinities, so

that when heat is applied to these materials in accordance with my process the chemical affinities are developed or increased up to the point necessary for eilieient action.

9o As a material for filling the cartridges, po-

tassium chlorate mixed with paraiiine-oil gives goed results. I mix themin the propor tion of about fifteen parts, by weight, ot' chlorate to one of oil.

For doing moderately heavy work l have used cartri @es with shells two and threefourths inches inside diameter and four feet long in the clear and holding about eleven pounds ot' the above described mixture. loc

Throughout the mixture and insulatedfrom the shell of the cartridge I' employ Germansilver Wires e e e e of No. I8 gage, insulated yof current. In the form of cartridge shown in lFig. 1 I arrange the entire length of ,wirez for convenience, in four spirals; each coiledv .about three-quarters of an inch in diameter,

and the'four coils are joined in series. These coils are placed lengthwise in the shell and fastened at the lower end toa wooden disk c' that fits the shell, so as to permit the heat when applied to reach with approximate uni forniity the entire mass of the charge. In the other form of shell the heating-coils of German-silver wire are shown arranged in large spirals,which are placed concentrically in the shell. This may, perhaps, produce a more uniform distribution of the heat, throughout the masaof active material; but being more flexible it is more readily displaced in filling the cartridge. Other dispositions .of wire to attain the result of approximate uniformity of heating will readily suggest themselves to electricians. After the spirals are placed the charge, which is a granular substance somewhat resembling C coffee-sugar,- is poured into the shell. Some care is necessary in filling the shell to avoid disturbing the approximate symmetrical. .distribution 'of the coils. The top covering or plug has lead lwires f f carried through and tightly fitted into it, and .after the shell is filled the top plug is pressed into place and the shell is then deposited in its final position for doing work.

The four-foot cartridge above described I place in the bottom of suitable holes bored -for the required distance into clay or rock.

Care needs to be taken to have the wires well insulated and uniformly distributed throughout the mass of the charge. The amount of resistance in the heating-wire is plainly, a matter of adjustment on the part of the engineer, and would be varied according to circumstances alecting the special features of the work to be done. A large proportion of the blasting requires a simultaneous firing of a number of charges. For such simultaneous work a suitable. number,` say twenty, holes are bored, and the cartridges with. lead wires attached are placed one or more in each hole, according to the depth of the ledge which is Lo be thrown out. For 'a vsource of electric current I use a dynamo-machine g, and a current of I. one hundred and twenty ampres at a pressure of one hundred and ten volts at the machine I have found'sutiicient for firing twenty four-foot charges simultaneously. -I divide this current through 'the twenty charges in multiple, so as to give each charge' -a current of about six ampres. Diagraml safety than such detonators.

Fig. 9 shows the arrangement of the 4wires and circuits. p circuit from the dynamo togetherwith a rheostat g2, by which the strength of the current in the heating-circuit g3 g4 may be adjusted to and maintained at the proper amount. .1

It will be understood that .as the tempera-l ture of the heating-coils and the s urrefinding mass in the lcartridges increases the resistance between the terminals of.` the heating?,-y coils will change, which change will necessitate a continual adjustmentof thecurrent .strength. When absol utely ing is desired, the heating is coniinuedjgnearly but not quite to the degree at whichthe-charge An ammeterg"iseennected in the will explode spontaneously. I have-found c that a temperature of labout 400 in the'iear- .8

tridges such as I have described vis sufficiently high to produce high eliciencynand that itis"l j not high enough to bring about spontaneous discharges. A s a rule, the closer the approximation to the point of spontaneous combination the greater will be the efficiency of the discharge.

The degree of heat which l have y .y employed in practice is'reached in about thirty minutes application of the current. '\Vhen the charges are heated to the required teinf ICO .IOS This mixture is a slow-burning one when lighted in the open airbut when heated and confined within the heated cartridge it acts instantaneously and gives the necessary impetus to nrc the entire charge invwhichfit is embedded. Within the charge of the igniter is a piece of No. 33 iron wire adapted to receive a current of electricity for irin g. The arrangement of the branch circuits 7c la containing the ignitersl. show in Fig. 9, together with the switch. me t0 use an igniter such as I have described for firing a charge of explosive material.

, When applied to dynamite my practice is to substitute dynamite for the potassium chlorate and oil, and I -may substitute detonators made of fulminate of mercury, such as are ordinarily employed .in iiring dynamite, in place of igniters. My igniters, however, may be used with dynamite with greater I believe it is original with -My method of applying the rin current y in multiple arcinstead of in series as is the practice with dynamite) enables me to secure 'greater certainty of firing, since the burning 0E of any one firing-Wire by an iniiniteei'nial period et time in advance of another. does not deprive the other tiring-wire of current.

l have 'used ammonium nitrate and potes Lfor expansion, thereby slum nitrate and manganese diolide in place of the. potassium chlorate. Instead of par'- alilne-oil I have used powdered carbon. I have. also employed .mixtures composed of the above-named sources of oxygen mixed in various proportions. For applying heat I have used electricity on aceou nt of the couvenience with which it can be applied to the charge `when deposited in place for doing its work. It is evident, however, that other methods oi heating might be employed. Sonie oi these other methods would be more readily available in tiring ordnance, especially in fortifications and on ships. For instance, the necessary heat energy could be derived from the sudden transformation of motion into heat, as when the shell penetrates an armor-plate, or by a sudden heavy compression analogous to that obtained by the `operation of the fire-syringe. An advantage of the electric heating is that it is so fully under control. The charge, consisting at the start o' inert material, may be prepared for tiring in the course of a few seconds, or heat may be applied sufiiciently slowly to blow.

the plugs by simple vapor-pressure. For ordnance wort; this enables me to secure by simple adjustment the entire range otl action which included between slow-burning and quich.- burning {or detonating) explosives, meal-powder being at one end of'the range and oxygen and hydrogen gas being perhaps at tue other end of the range. I can by adjustment of the rapidity and degree of heating attain results at either extreme or at any desired intermediate point between the extremes.

The advantage which my invention altords in rendering possible the use of materials which at ordinary temperature are lsafe `to handle has as a consequence the further advantage oi safety in removing a charge or a .aart of a chl rge which has failed to explode, and any unexploded fragments of material which may be scattered by a charge are also harmless. l

I an. aware that it is old in the art to usc the el citric current to ignite explosive material either by means of a wire heated to incandescence or by means of a spark. In either case the process has been one of sim- ,'z-le combustion and the electric current has simplythe initial cause of the combustion. The process and result of my present invention dilier from simple combustion and explosion o1' compoundelements,iirst,iu heating the charge uniformly throughout the mass, thereby weakening the stability of thel combinations of or dissociatiug all the elements which are to enter into new combinations; second, in storing up heat in thematerial, thereby enabling the expanding gases tp absorb or render latent the heat required greatlylessening the demands upon the heat developed by combustion. This is an important feature of my process, which by way of preparation for the `explosive union ofv elements stores up a supply which is available at the critical moment of expansion of the gases. The result of this is that the explosive force is made much greater than it would bc'if a portion of the heat of combustion were required to furnish the latent heat of the expanding gases, as is the case inthe process of producing` explosionsby combustion. A third distinction between the processes of producing explosions .heretofore known and the process of my invention lies in the freedom and readiness with which the dissociated `elements of the materials tend to combine under the influence ofthe continuous application of heat as contrasted with materials which are allowed to cool after their elements are dissociated or the stability of their1 combinations is weakcned. In the case ot the combustion or detonation of simple elements, aspxygen or hydrogen, my process provides a supply of heat to take the place 'of that rendered latent by expansion and facilitatesthe instantaneous combination' of the elements by heating them throughout their mass.

.There is, of course, a greater gain in ,elhciency by my process when the materials employed for the charge are capableI of being raised to a high temperature, and so of receiving a larger store of heat than when ina- Vterials of another character are used, such as cannot be heated to a great degree. The heat energy, amounting approximately to three hundred and fifty foot-tons, which in the course of half an hour is stored in each one of the cartridges which I have previously described -(less what little may have been lost through the insulation) is expended in a small fraction of a second, thus enormously increasing in the Ways I have mentioned the eiiciency of the charge by being available at the instant of time when it is needed.

My process is especially applicable to such compound substances as require a high degree of heat for complete dissociation of their elements, and is therefore available in the use of compounds which at ordinary temperatures can be handled with absolutely safety, but which are not commonly used as explosives on account of their slow combustion.

I consider the broad featureof my invention to be the preparation of the explosive material in the place where it is to be used by the storage of heat energy applied throughout the mass of the material, and by preparation I mean bringing the material to the verge of explosive combination of its elements or some of them. As specific processes, subsidiary to this broad generic invention, are various methods of brineing about'the actual explosive union of the elements of the material, one of such specific processes being that described herein, wherein an igniter or detonator is used for iringthe charge.

In my appisation Serial No. 430,094 I have described and "claimed a method limited in its application to substances which are con- ICO IIO

ductors of electricity, and which is subordinate to the broad invention of this ense.

In my application Serial No. `230,090 I have described and claimed@ method which is specie-:ind subsidiaryv to the-generic invention ot' the present ense in that it isdireeted to the process of producing the actual explosive union of the elements of the materials by means of continued application of the heat until the explosive union of the elements is determined, it process which is practical and advantageous for single-shot firing,but which does not lend itself so readily to the produ@ lion oi' simultaneous discharges of several cartridges, as does the method herein described, in which ignitcrs or detonstors are used.

Having thus described my invention, what Iclaim as new, and desire to secure by, Letters PzitentLis* 1. The herein-described method of produc ing explosions `which consists in confining substances which do not combine explosively et initial temperature, uniformly heating said substances to n temperature neztrthzit at which explosive union of the substances takes place when the same lare ignited, mid then causing the explosive unionof seid' substances; sul)- sta'ntally as described.

2. rlhe herein-described method of produc-f in g explosions which consists in confiningsubf stances which do not combine explosively at'. initial temperature, -subjecting seid4 sub.-

stances lo the heating etect of su electriecurrent to raise the same to a, temperature near 'that at which explosive union trikes place,v

and then by a sudden 'application of heat by the passage of an electric current causing the explosive union of said substances; substan- *i tially as described.

$5. I n an electrically-exploded cartridge, the

combination with an incloosing shell, of sub-- stances contained 'therein which4 do not exploslvely combineet initial tempereture, elecn trical conductors embedded in said substances 

